A power supply is a device that provides electrical energy to power electronic devices. It converts electrical energy from a source, such as a wall outlet or battery, into a usable form for devices like computers, televisions, and appliances. Power supplies ensure that these devices receive the correct voltage and current needed for operation. There are different types of power supplies, including AC-DC converters, which change alternating current (AC) from the wall into direct current (DC) used by most electronics. Switching power supplies are commonly used for their efficiency and compact size, making them ideal for modern gadgets and equipment.